Finite element reliability analysis of shallow foundation settlements

This paper presents the settlement analysis of shallow foundations resting on granular soils within the framework of probability theory. Two probabilistic approaches of reliability analyses such as point estimation method (PEM) and first order second moment method (FOSM) along with the non-linear finite element analysis are used to evaluate the reliability index (β). The non-linearity of the soil is represented in the finite element model using the hyperbolic model. The hyperbolic parameters: the modulus number K, the exponent n, and the angle of internal friction φ are considered as random variables in the analysis. Numerical examples of strip and circular footings are presented to illustrate the practical applicability of the methods. The probability that the settlement at the centre of the footing may exceed a specified acceptable value is analysed. The results indicate that the random variable φ has a pronounced effect on the expected settlement as compared to the random variables K and n.